This invention relates to illuminator boxes which are commonly referred to as "light" boxes. The illuminator or light box is a commonly used device. One application is in reading x-rays. This has found increasing use in recent years as a tool for use in diagnosing medical problems and injuries of the body. The light box generally used in these applications consists of an enclosure housing several florescent light bulbs with a translucent plastic or glass screen on one face of the light box. The screen is illuminated when the lamps are energized and the x-ray is held against the screen for viewing. The light bulbs are either "on" or "off" and the light box has no ability to vary the amount of light striking the screen to illuminate it. Thus, the x-rays could only be read with one light intensity illuminating the screen and this light intensity was not variable. This presented a problem in that under or over exposed x-ray films could not be easily read as the illuminating light source was not adjustable to compensate for the poor quality of the x-ray exposure. Also, some x-rays have extremely dense or dark areas which are difficult to read on conventional light boxes as neither the intensity nor type of light is variable.
A second application of light boxes is in the graphic arts field. These are commonly referred to as "light tables." Often artists desire different colors of background lighting when creating their works. The conventional light tables used by artists have only one color of light source available, usually white. If other background lighting is required, the artist must remove the bulbs in the light table and replace them with the colored bulbs desired. Obviously, this is a major drawback, as the labor required to change bulbs is often substantial and therefore a major hindrance to the user.
When creating transparent overlays, a single colored background light is not always desirable. It would be a great aid to have lighting which could easily provide various color backgrounds. The artist can then easily try varying background color schemes while alternating overlays to determine the effect on the work. As more and more overlays are added to the work, the light intensity passing through the overlays is decreased. With conventional light boxes the light intensity cannot be varied and thus, the number of transparencies which can be built upon is solely dependent on the transmissivity or clarity of the overlays and the initial intensity of the light source. By putting in too strong of a light source, the initial overlay would be too bright and offensive to the artist. By using too dim of a light source, the light would not be bright enough to pass through several layers.
The present invention relates to a light box or light table for use in x-ray diagnosis, graphic arts color separation, parts inspection, photographic and hobby uses. It is particularly useful in any application wherein a light box is required which would have the capability of varying the amount of light illuminating the screen or in which various colors of light illuminating the screen are desirable.
According to one aspect of the invention, the amount of illumination may be varied by turning on different sets of bulbs. Thus, dark areas of x-rays or several overlays can be more easily read. Also, various lights, for example in medical diagnosis ultraviolet light may be substituted for the standard bulbs. Such a substitution can make the reading of some x-rays easier and more accurate, thereby improving diagnosis.
In another application of the invention, for example parts inspection, a soft, dim light might be advantageous for inspecting one type of part, while a brighter light might be required for inspecting a second dissimilar part. Without modifying the light box or installed illumination sources, applicant's invention could supply the required intensity and type of light by merely energizing the desired bulbs. In artistic applications, a blend of colors could be achieved by providing simultaneous light from two or more different lamps having distinct color values. By selectively choosing the desired lamps and color scheme, various end results can be achieved. Thus, the artist can easily experience the effects of individual or blends of colors on the work.
According to the specific embodiment illustrated in the drawings of this application and discussed in detail below, a light box is disclosed in which there are several sets of illuminating sources. Each set is identical to the other sets. Furthermore, each set contains two or more bulbs and it preferred that the bulbs be different in intensity, color or type of light emitted. By means of control switches, the sets of bulbs can be controlled so that the same type of bulb of each set can be separately energized apart from the other bulbs of the set. Alternatively, all the bulbs in each set can be energized. In this manner various light intensities can be achieved along with "blending" of colors or types of light. The number of sets can be varied along with the number of bulbs in each set.
Thus, it is an object of this invention to provide a light box having the ability to vary the intensity of light illuminating the screen. It is a related object to provide a light box having control means to vary the light intensity on the screen by controlling the number of light sources energized at one time.
Another object is to provide a light box having several colors of light sources which can be separately energized to provide blending of the selected colors. Another closely related object is to provide a light box having various light sources which can provide a specific type of light for improved medical diagnostic abilities.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.